A climate-controlled enclosure is more particularly intended to form a chiller unit or a freezer unit in which chilled or frozen products are respectively displayed, these products possibly being items of food or drinks or any other products that need to be kept cold—pharmaceutical products or flowers for example.
Although frozen products are increasingly being sold in units provided with what are called “cold” doors, comprising transparent insulating glazings, at the present time self-service fresh and ultra-fresh items of food are essentially sold in stores by means of vertical units that are open-fronted. Provided with a curtain of refrigerated air as the front face in order to isolate the items of food from the warm ambient environment of the store and to keep the items of food at their optimal preservation temperature, these units are quite effective from this point of view and, in the absence of physical barrier, allow products to be accessed directly, facilitating the act of purchase.
However, the absence of physical barrier in these vertical chiller units leads to substantial heat exchange between the ambient environment of the store and the much colder ambient environment generated inside these units, this having the following consequences:                this heat exchange must be compensated for by greater refrigeration in order to guarantee temperatures that are optimal for the preservation of items of food in the unit, this disadvantageously increasing the power consumption of these units;        the ambient environment of the store is considerably cooled locally (cold-aisle to effect), this leading to consumers avoiding venturing into these aisles except for essential purchases, reducing impulse buying. This local cooling of the aisles in question has grown worse over the last few years as the strictness of food-safety regulations has increased and led to the storage temperature of foodstuffs being further decreased;        moist air from the ambient environment of the store is siphoned off by the cold-air curtain on the front face of the unit, this leading to a rapid saturation of the unit's heat exchanger (also called an evaporator) which ices up, which then significantly decreases the efficiency of the heat exchange. It is therefore necessary to frequently de-ice the evaporator, typically twice a day, this leading to an increased power consumption.        
Confronted with these drawbacks, unit manufacturers have attempted to provide solutions, in particular involving optimizing the air curtains and heating the aisles with radiant heaters or hot-air blowers. The progress made with respect to customer comfort nevertheless remains limited, and is to the detriment of power consumption. Specifically, the heat produced by these heating systems, which guzzle power, also heats the units, and thereby leads in the end to even more power being consumed to refrigerate these units.
Providing these open-fronted units with conventional cold doors allows these drawbacks to be effectively addressed. However, these solutions, which are tried and tested in freezer units for frozen products, have been slow to be adopted in chiller units. These doors have the disadvantage of placing a physical barrier between the consumer and the self-service product, possibly having potentially negative effects on sales.
Furthermore, these doors are manufactured to a design similar to that of the windows used in buildings: a frame made of profiles, generally made of anodized aluminum for reasons of esthetics, resistance to aging and ease of manufacture, frames the entire periphery of a double or triple glazing. The frame is generally adhesively bonded directly to the periphery and to the external faces of the glazing; it participates in the rigidity of the structure and allows the interlayer means (spacers) placed at the periphery of the glazing and separating the glass sheets to be masked from sight.
However, such a structural frame significantly decreases the vision area of the glazing.
It has thus been proposed, to improve the vision area of glazings, to manufacture insulating glazings with transparent spacers at least on their vertical sides, furthermore creating a visual perception of a transparent surface continuity over all of the refrigerated glazings placed side-by-side with one another forming a display case.
The spacers are fastened with adhesives such as acrylic adhesives, which furthermore perform a watertight function, the adhesive being at the interface between the spacer and the internal face of the glass sheets of the glazing. To perfect the sealing, a transparent additional seal is sometimes added such as a silicon seal positioned on the external side of the air-filled cavity of the glazing, on the edge of the spacer and between the two glass sheets.
The addition of a second leaktight barrier in particular made of silicone supplements the leaktightness by providing leaktightness not only to water but also leaktightness to gases and to water vapor. Specifically, certain plastics from which the transparent spacer is made are not completely leaktight to gases and to water vapor.
However this additional seal, although transparent, generates a negative visual impact for the consumer facing, and above all positioned angularly to, a refrigerated enclosure with such a glazing.